Burner



Oct 1966 J. J. WOLFERSPERGER BURNER 4 Sheets-Sheet 1 Q Filed Dec.

0%, ATTORNEYS 1966 J. J. WOLFERSPERGER 3,276,593

BURNER 4 Sheets-Sheet 2 Filed Dec. 2 1964 mam. w a W, N \V J I NE vfi I, km

INVENTOR.

JOHN J- WOLFERSPERGER 0%, ATTORNEYS 1966 J. J. WOLFERSPERGER 3,276,693

BURNER 4 Sheets-Sheet 3 Filed Dec. 2

INVENTOR. v JOHN J- WOL FERSPERGER AT TOR/V575 1966 J. J. WOLFERSPE-RGER 3,276,693

BURNER Filed Dec. 2 1964 4 Sheets-Sheet 4 42 -i INVENTOR.

JOH/V J-WOLFE/PSPERGEH 47 TOH/VEYS United States Patent 3,276,693 BURNER John J. Wolfersperger, 21 Strawberry Circle, Mill Valley, Calif. Filed Dec. 2, 1964, Ser. No. 415,367 12 Claims. (Cl. 239-9) This invention relates to an improved fuel oil burner and to an improved combination oil-and-gas burner, more particularly of the type used with boilers and similar apparatus. It also relates to an improved method for more eflicient burning of fuel oil.

The present invention is an improvement over the oil burners described in my previous Patent Nos. 2,499,207, 2,581,316, and 2,787,318, which were designed to burn fuel oils ranging from No. to No. 1, and also more volatile fuels such as gasoline, naphtha, etc. All these fuels were produced from crude oil by distillation processes; so they contained no solids and were burned com pletely and very efficiently in my previously patented burners, leaving no residue Whatever in the burners or boilers.

Currently, however, modern refineries have adopted less costly catalytic processes for cracking crude oil and other oils and for obtaining the various grades of fuel oils. The catalysts comprise very finely ground refractory materials; one refiner has stated that if the surface of the particles in a cupful were spread out, it would cover fifteen acres. These catalysts promote chemical reactions which convert the crude and residual oils into products such as gasoline, heating fuel, and ingredients for petro-chemicals, and the catalysts remain unaltered and are recoverable for re-use. However, due to the fineness of the catalyst particles, a small percentage of the finest particles tends to remain in the decanted oil and various undistilled products, and to date, refineries advise they have not been able to remove the catalyst residue from such products. This very fine residue apparently does not settle out from fuel oil during storage but is carried along in apparently uniform suspension, passing on through the pressure-atomizing nozzles of the burners and being present in the nozzle spray in the burners.

In conventional burners, the catalyst has been carried into the boiler tubes, apparently as a dry fine powder; there, some of it has coated the tubes and some of it has passed out the vent or stack. Periodically, this catalyst coating in the boiler tubes of conventional boilers has had to be scraped out in order to prevent a throttling buildup, brought about by the customary slow flow of the prodnets of combustion through the conventional boilers.

1 In my previously patented devices, mentioned above, the combustion products flow through the tubes at a velocity many times as fast as in the conventional boilers, with the result that the build-up of the catalyst deposit in the boilers never exceeds about thickness; this thin deposit becomes an additional heating surface, increasing the heat transfer, as evidenced by a drop of several degrees in flue gas temperature during the build-up of this thin deposit. After the initial thin build-up, there is no further build-up, and the high velocity of flow carries the rest of the catalyst in suspension through the boiler and out the vent or stack.

However, in my previously patented burners, there was a problem with this catalyst in the burner, where after ignition at the nozzle tip and before the flame passed through the burner sleeve, some of the heated spray of fuel and catalyst (being heavier than the former clean distilled fuel spray) has broken through the air envelope surrounding the flame and has coated approximately 20% of the sleeves inner surface at the forward end of the 3,276,693 Patented Oct. 4, 1966 burner sleeve, with a hard black slag. This slag coating has continued to build up until it interfered with and upset the air flow to the point where a carbon deposit was brought down; then it became necessary to shut down the burner for removal of the slag and carbon deposits.

In conventional oil burners, the catalyst residue was not a burner problem-though it was a severe boiler-tube problem--because the conventional burners discharged the fuel from its pressure type nozzle (and ignited it at the nozzle tip along with all the combustion air) into a relatively wide and long refractory-lined combustion chamber. Soon after ignition, this refractory-lined chamber became hot enough to break down, or to prevent the formation of, the previously mentioned slag, so that the catalyst residue passed on into the boiler tubes.

In my previously patented burner and combustion chamber no refractory lining was used, and I have now found that this important advantage can be retained by preventing the flame within the burner sleeve from coming in contact with the inside surface of the forward end of the sleeve. The air forming the air envelope around the flame inside the sleeve has entered the sleeve from the annular space around the sleeve at the end of the sleeve spaced closest to the end plate of the burner, and I have found that the problem apparently is caused by the original whirling high velocity of this air being pretty well spent by the time it reached the forward end of the sleeve.

In the present invention I solve this problem by providing a stouter, faster flowing air envelope at the forward end of the sleeve to protect the sleeve from slag deposit. This faster flowing air envelope is provided by tapping the annular flow around the sleeve close to this area. The tapping is accomplished by using a shorter sleeve, about 20% shorter than before, and by combining therewith a short sleeve of larger diameter, spaced concentrically around the distal end of the shortened sleeve and secured to it by suitable spacers. The added portion is only long enough to lap the shortened sleeve a short distance, and the combined over-all length of the two spliced sleeves is identical with the length of the original sleeve. For example: in a 20 horsepower burner the original sleeve could be 6% OD. and 8% long; in my new 20-horsepower burner, the sleeve would be about 1 /2 shorter, and the outer sleeve would be 2 /2" long; 6%" I.D.; and the lap would be 1".

With these alterations, a newly added air envelope comes around the flame fresh from the annular air passage, and is of such high velocity that it prevents the slag particles in the flame from coming in contact with the sleeve. The final air-split around the distal end of the added portion of the sleeve is of ample volume and velocity to likewise envelop the flame and prevent the slag particles in the flame from coming in contact with the inside surface of the frustoconical outlet of the burner.

Due to the preparation given the flame after ignition and within the burner, the combustion has been so well advanced that the temperature of the flame exceeds 3,000 F. immediately upon passing through the burner outlet throat, and this high temperature promptly burns the fuel out of :all Would-be slag particles so that the catalyst residue is returned to its original condition of a dry fine powder which passes into the boiler tubes, some of it coating the tubes but only to a thickness of & (as described above), and the rest of it passing out through the vent or stack.

This invention also provides an oil burner inside which it is practical to mount the gas-tube described in my gas burner patent application Serial No. 380,142, filed July 3, 1964, to thus form an improved oil and gas combination burner. Also, I provide an improved method of operation of such a combination burner.

In most conventional oil-gas combination burners, in order to change from one fuel to the other, it is necessary to shut down the burner and change some of the equipment inside the burner, or to make :a complete change of burners. In this invention, neither fuel equipment inside the burner interferes with the equipment of the other fuel, so that to change fuel it is unnecessary to shut down the burner, and the fuel change can be made by closing a valve in one fuel line and opening a valve in the other fuel line, both valves being outside the burner; and the closing and opening of the valves can be performed simultaneously because the burner can operate using part oil and part gas as long as the sum of the two fuels does not exceed the fuel capacity of the particular burner.

The oil burner in this application is the basis of the combination burner, due to the split sleeve requirement to handle the catalyst residue in the fuel oil. (In a burner for gas only, the sleeve would not have to be split, although the split sleeve of the oil burner has no ill eifect on the combustion of the gas.) The only changes needed to conver the oil burner to a combination burner are: (1) the addition of a hole and a collar in the end-plate to admit and anchor the gas supply pipe of the gas-tube; (2) a hole and a collar, also in the end-plate, for one ignition electrode for gas ignition; and (3) a hole in the end-plate for a sight-glass to observe the ignition spark for the gas, all through holes being located identically as the three holes for corresponding purposes in the end-plate of the gas burner application Serial No. 380,142. The individual gas burner and the individual oil burner may both be designed so that they can be converted to combination burners without any construction interferences.

An object of the present invent-ion is to provide a superior fuel oil burner which achieves complete burning of the fuel within a short distance of travel beyond the burner outlet throat and does so in an efiicient manner conducive to the maxi-mum production of heat from the flame, and which also prevents encrustation of slag in the burner when catalyst is present in the oil. The combustion air is fed to the flame in several steps, achieving an approximation of providing the oil with air in the proportion which the flame requires and as the flame needs the additional air, and also preventing catalyst from depositing as slag in the burner.

Another object is to obtain the same results in a combinat-ion burner which can burn either oil or gas.

Another object is to provide a combination burner that can be switched from oil to gas and vice versa during operation.

Another object of the invention is to provide a burner unit which itself is kept cool and therefore does not require outer insulation or an inner refractory lining, though it feeds fuel to a very 'hot flame and sends more heat than has been normal into a combustion tube, which combustion tube also requires no refractory lining.

Another object of the invention is to rapidly heat the initial flame and to keep the flame temperature increasing rapidly While feeding additional combustion air to it.

Other objects and advantages of the invent-ion will appear from the following description of a preferred embodiment thereof.

In the drawings:

FIG. 1 is a fragmentary view in perspective and partly in section of an oil burner embodying the principles of the invention. The burner is shown installed at one end of a boiler fire tube, the tube sheet and fire tube being broken off in order to conserve space.

FIG. 2.is a view in elevation and in longitudinal section of the apparatus of FIG. 1.

FIG. 3 is a fragmentary view in perspective and partly in section, similar to FIG. 1, of a combination oil-and-gas burner.

FIG. 6 is a view in cross section taken along the line 66 in FIG. 4.

FIGS. 1 and 2 show a burner 10 mounted in one end of a cylindrical fire tube or furnace 11 of a boiler, the furnace 11 being mounted in an opening 12 of a tube sheet 13 of the boiler. The furnace or fire tube 11 is provided with a burner mounting flange 14 to which is bolted (or otherwise secured) a mating radially extending flange 15 that extends out radially from the exterior wall of the burner unit 10.

The burner unit 10 is provided with an outer shell 16 having a cylindrical portion 17 and a frustoconical portion 18 meeting the cylindrical portion 17 at the flange 15. The frustoconical portion 18 preferably extends into the fire tube 11 and is provided with an outlet opening 20 from which the flame issues into the furnace 11. With the present invention, the flame need only extend beyond the outlet 20 for a distance about the same as the length of the outer shell 16, the oil being entirely burned within about that additional length of travel beyond the outlet 20.

The cylindrical shell portion 17 is provided with an air inlet opening 21 (exactly as in FIG. 6) and the air is supplied from a fan or other pressure device (or induced draft, if desired) to this opening 21 tangentially by means of an air inlet fitting 22 which has an upper tangential Wall 23 and a lower wall 24 which converges toward the wall 23 as they approach the inlet opening 21. Diverging side walls 25 (FIG. 1) of the fitting 22 lead from a tubular inlet 26 to the inlet opening 21.

An end plate 30 is secured to a flange 27 at the inlet end of the shell portion 17 with proper gasketing 31 between them. The end plate 30 is provided with a suitable sight glass 32 for observing the ignition point and the normal operating flame. It is also provided with suitable openings for some other members that will be described. In addition, it forms the end wall of a series of (e.g., four) radially extending air scoops 35 which are shaped to provide radially extending openings 36 that pick up air at the outer periphery of the cylindrical shell portion 17 and then conduct the air radially inwardly and eject it in a generally axial direction through openings 37 which are fairly close to the center line or axis 38 of the shell 16. These air scoops 35 provide a generally axial flow of air centrally through the burner unit 10, and overcome a naturally reverse or rearward flow generated by the tangential flow of the inlet air.

A cylindrical sleeve 40 is mounted concentrically within the cylindrical portion 17 by means of a series FIG. 4 is a view like FIG. 2 of the burner of FIG. 3.

of radially extending pins 41 and a bracket 42. At the burner inlet end, the edge 43 of the sleeve 40 preferably abuts the air scoops 35 and provides in between them a series of spaces 44 by which air can pass in toward the axis 38 by a different route. At its other end, the sleeve 40 stops at an edge 45 which, in this invention, lies within the cylindrical portion 17, as shown in FIGS. 2 and 4. The edge 45 may be about 2 /2" axially from the frustoconical portion 18, for example, in a 20 HP. burner. Thus, air coming in through the opening 21 enters an annular air duct 46 between the sleeve 40 and the cylindrical shell portion 17. Since the air enters the duct 46 tangentially, it tends to whirl around in it, and a whirling motion is imparted to it that continues when it leaves at both ends, 43 and 45. This whirling motion increases turbulence and, as will be seen, thereby improves the efiiciency of combustion. Some of this air from the duct 46 enters the inlet 36 for the air scoops 35, as just described; some of the air also passes radially inwardly via the spaces 44 while'whirling. Other portions of the air leave the space 46 at the end 45, for a purpose to be described later and also form an air envelope about the flame. This air envelope, in turn, air-cools the frustoconical wall 18, preventing overheating of the wall 18 by the flame. The air in the space 46 also aids in cooling the sleeve 40.

An oil nozzle 47, preferably of the pressure atomizing type, is provided axially of the burner 10, close to the end plate 30. Oil from a suitable storage tank is fed through a conduit 48 to the nozzle 47, whence it is sprayed out into the sleeve 40. A pair of igniter electrodes 49 and 49a are provided adjacent the nozzle 47.

In my former patents, the part corresponding to the sleeve 40 extended on into the conical portion 18 of the shell 16, with its edge lying about Ms" from the conical wall 18 in a 20 HP. burner. When oil containing the fine catalyst particles in suspension was burned, this mixture was able to break through the air envelope at the distal end of the sleeve and coat about one-fifth of the sleeves inner surface with the hard black slag material, mentioned earlier, the slag building up until it was able to upset the air flow and bring down carbon deposit, necessitating a shutdown for removal of the slag and carbon.

In the present invention the build-up of slag is prevented, and consequently no carbon deposit forms either, as a result of a novel structure which produces a surprising change in operation. In the first place, as noted earlier, the edge 45 of the sleeve 40 is located well within the cylindrical portion 17 of the shell 16, equivalent to cutting off the last 2 /2, e.g., of the sleeve of a 20 HP. burner. Then, a short auxiliary sleeve 50 is installed around the distal end 45 of the sleeve 40 and extending beyond it into the conical portion 18, stopping just where the sleeve 40 used to stop, and (due to its greater diameter) the edge 51 of the auxiliary sleeve 50 lies about one-half inch from the conical wall 18. The other end 52 of the auxiliary sleeve 50 overlaps the sleeve 40 about an inch and is supported by it through welded spacers 53, leaving a space or .air passage 54 about an inch long and about Mr" wide in a 20 HP. burner. Spacers 55 support the auxiliary sleeve 50 in the shell portion 17, leaving a space or air passage 56 around the sleeve 50.

With this alteration, the added air envelope around the flame is fresh from the annular air passage 54 and is of such high velocity that it prevents the slag particles in the flame firom coming in contact with the sleeves 40 and 50. The final air-split around the distal end 51 of the auxiliary sleeve 50 is of ample volume and velocity to likewise envelop the flame and prevent the slag particles in the flame from coming in contact with the inside surface of the frustoconi'cal outlet 18 of the burner.

Due to the preparation given the flame after ignition and within the burner, the combustion has been so Well advanced that the temperature of the flame exceeds 3,000 F. immediately upon passing through the burner outlet throat 20, and this high temperature promptly burns the fuel out of what otherwise might be slag particles so that the catalyst residue is returned to its original condition of a dry fine powder which passes into the boiler tubes, as described earlier.

The invention makes it possible also to supply a novel combination burner 60, shown in FIGS. 3-6, which can burn either oil or gas, switching from one to another whenever economies or convenience or any other reason gives a reason for changing. In contrast to those conventional oil-gas combination burners in which one must completely shut off the flow of fuel to the vburner in order to change burners or some of the equipment inside the burner when changing from one fuel to the other, the fuel change in my new combination burner can be made by closing a valve 61 in the oil fuel line 48 and opening a valve 62 in the gas fuel line 63, or vice versa. Both valves 61 and 62 are outside the burner 60, and the closing and the opening of the valves 61 and 62 can be performed simultaneously because the burner 60 can operate using part oil and part gas as long as the sum of the two fuels does not exceed the fuel capacity of the particular burner 60.

The oil burner may be considered the basis of the combination burner 60 due to its need for the two sleeves 40 and 50 so that it can operate properly when there is catalyst residue in the fuel oil. In a burner for gas only, as shown in my application Serial No. 380,142, the sleeve 50 is not needed and the sleeve 40 may continue into the space defined by the conical shell 18; however, the use of the sleeves 40 and 50 of the oil burner 10 has no ill effect on the combustion of the gas; so for combination use, they are employed. The only changes made to the oil burner 10 in order to enable installation and use of a gas tube 70 are: (1) the addition of a hole 64 and a collar 65 in a modified end-plate 30a to admit and anchor the gas supply pipe 78 of the gas-tube 70; (2) a hole 66 and a collar 67, also in the end-plate 30a, for an ignition electrode 81, for gas ignition; and (3) a hole 68 in the end-plate for a sight-glass 69 to observe the ignition spark for the gas. All three holes 64, 66, and 68 may be located as in the end-plate of a gas burner like that of application Serial No. 380,142, so that either an individual gas burner or an individual oil burner can be converted to a combination burner without any construction interferences.

In the combination burner, an annular gas tube 70 is then located concentrically with respect to both the cylindrical sleeve 40 and the shell 16. A series of short pins 71 supports the gas tube 70 inside the sleeve 40, preferably spacing it only about one-quarter inch from the sleeve 40, in a burner of 20 HP. capacity. Thus, between an outer wall 72 of the gas tube 70 and a sleeve 40 there is an air passage 73 which serves two purposes. For one thing, it aids in kwping the sleeve 40 cool beyond the gas tube 70, as a result of the air envelope it forms about the flame, since circulating cool air is passing through this insulating space 73 from the spaces 44 toward the outlet opening 20. This space 73 also provides another source of combustion air, some of which is fed to the flame as the flame leaves the distal end wall 74 of the gas tube. The gas tube 70 is substantially shorter than the sleeve 40, and its end wall 74 is axially spaced a substantial distance from the edge 45. Here, again, a whirling current of air is fed to the flame, and it is fed to it after the initial feeding of air and before the air that comes olf the edge 45 of the sleeve from the air duct 46.

The gas tube 70 has, in addition to the outer wall 72 and the end wall 74, another end wall 75 and an inner cylindrical wall 76. In between the inner and outer walls 76 and 72 of the gas tube 70 is a gas manifold passage 77 into which a gas supply tube 78 leads. Preferably the tube 78 extends axially and leads in through the collar 65 and the opening 64 in the end plate 30a, with a set screw 79 in the collar 65 for forward and back adjust ment of the gas tube 70. The gas tube 70 is centered by the pins 71 so that it can be adjusted forward and back in order to achieve the best results. Typically, the end wall 75 will rest against the air scoops 35, or close to them, but this may be adjusted if desired.

The inner wall 76 is provided with a extending radially directed slots 80. slots 80 may be about wide, and they may be spaced about A" apart all around the circumference. Gas pressure definitely imparts a radial flow to the gas through the slots 80 toward the center of the gas tube 70.

An ignition electrode 81 extends through the opening 66 in the end plate 30a and is provided preferably with a single wire 82 that is bent down so that its end 83 is in close proximity to the lowest slot of the radial slots 80 and fairly near its end wall 75. The spark crosses from the end 83 to a bafile 84, which may :be of metal wedged and tack-welded into the end of the lowest slot 80 and projects up vertically a short distance and decelerates and deflects some of the whirling air to a slow radial ripple or flow, cooperating with a baffle which depends from the wall 76 just below the baffle 84 at its inner end, helping to sweep gas up into the slot-s 80 on each side of the baflie 84 and thereby provide the properly enriched mixture for a dependable initial ignition. The combination of diversion of gas into the slots 80 closest to the series of axially As an example, the

baffle 84 and the diversion of air into this gas, makes ignition smoother and quicker and positively dependable for starting ignition of the gas for the entire burner.

During operation with gas, gas enters the supply tube 78, passes into the manifold passage 77, and is distributed around inside the gas tube 70, there being sulficient pressure to provide an even distribution. The gas then issues radially through the long axially extending radial slots 80 and passes in thin sheets toward the center or axis 38 of the burner unit 60.

Meanwhile, air enters the air inlet tube 26 and flows through the air inlet opening 21 into the air duct 46. Some of this air enters the air scoops 3S and passes radially into a point approximately near the axis 38 of the burner 60. Another portion of the air passes radially inwardly via the spaces between the air scoops 35, and thence part of it flows into the space 73 between the sleeve 40 and the outer gas tube wall 72, while another part of it passes into the interior of the gas tube 70, whirling and flowing fairly close to the inner wall 76. This air is the initially burned portion, and then as the flame burns inwardly, it begins to consume the air supplied by the air scoops 35. Since the air-scoop air flows substantially axially while the other adjacent air is whirling, a turbulence is set up which improves the burning efficiency and enables the combustion air to gain the necessary access to the unburned gas. Also, the axial movement of both these air currents sends the flame in the proper axial direction toward its eventual outlet opening 20.

As the burning mixture passes beyond the end wall 74 of the gas tube 70, it encounters additional air which has passed through the passage 73 and this additional air forms an envelope of air around the flame between the flame and the sleeve 40, aiding in keeping the sleeve 40 cool. This additional air is thus fed to the flame at the proper time so that it can be used to continue the burning process. As the flame moves further axially, it meets two final splits or fractions of air at the very time when it is ready for them. These final splits of combustion air have passed from the duct 46 and are now moving spirally at a rapidly increasing velocity through the space 54 and also off the end 51 of the auxiliary sleeve 50, the latter being whirled spirally; its turbulent path assures good mixture. Since it reaches the flame just when the flame needs additional air, combustion is rapid and efficient.

Combustion continues on beyond the outlet opening 20 for about a distance equal to the length of the shell 16, as the flame burns inside the fire tube 11. This is a very short length when compared with prior art devices. For example, the cylindrical portion may be only one foot long, the frustoconical portion about another five and a half inches long, and the combustion may be complete within about eighteen inches after leaving the nozzle outlet 20. This is a small fraction of the combustion space that is furnished by conventional boilers and means, for example, that a 60-horsepower burner of this invention can be used in a conventional boiler unit designed for 25-horsepower output and this boiler can thus produce 60-horsepower, which is 240% of its intended use, and it does this very efficiently.

Just as examples of some typical proportions, in a 60 H1. burner the gas tube 70 may have an inner diameter of about six inches and an outer diameter of about nine and one-half inches and may be about four and a half or five inches long. The sleeve 40 may be about ten inches long, the sleeve 50 about three and one-half inches long, the cylindrical portion 17 may be about twelve inches long. The space "73 may be about onequarter inch wide, and the air duct 46 may be about one inch Wide. These dimensions are changed, of course, in the design of larger and smaller capacity burners, and the burner unit may be designed to handle a very wide range of capacities. Thus, in a 20 HP. burner, the gas tube 70 may have an inner diameter of about four inches and an outer diameter of about five and one-half inches and may be about three and a half inches long. The sleeve 40 may be about seven inches long, the sleeve 50 about two and one-half inches long, the cylindrical portion 17 about eight inches long, the space 73 about one-quarter inch wide, and the air duct 46 about seveneighths of an inch wide.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

I claim:

1. An oil burner for use with boilers and the like, including in combination:

an outer shell having a generally cylindrical portion, and an axial outlet, said cylindrical portion having an air inlet opening,

a main cylindrical sleeve supported concentrically within said cylindrical portion and spaced radially therefrom to define an annular air fiow duct in communication with said air inlet opening,

an end plate closing one end of said burner and of said cylindrical portion, said sleeve being spaced axially therefrom to provide for radial inward passage of air from said duct,

an oil spray nozzle supported by said end plate and extending axially of said main sleeve, and

an auxiliary sleeve of larger diameter than said main sleeve and of smaller diameter than said cylindrical portion of said outer shell, concentric with and supported by said main sleeve at the end distant from said end plate to provide a short overlap and extending therebeyond to provide air flow in between said sleeves and also around the end of said auxiliary sleeve lying beyond said main sleeve.

2. The burner of claim 1 having a plurality of radial air scoops at said end plate leading radially in from said air inlet duct, each having an axial outlet near the axial center line of said burner.

3. An oil burner for use with boilers and the like and for burning oil containing catalyst fines, including in combination:

an outer shell having a generally cylindrical pre-fire- Wall portion and a frustoconical post-firewall portion with an axially aligned nozzle outlet of reduced size, said cylindrical portion having an end edge and having an axially extending tangential air inlet,

a main cylindrical metal sleeve smaller in diameter than the cylindrical portion of said shell supported concentrically entirely Within said cylindrical portion and providing with said cylindrical portion an annular air flow duct in communication with said air inlet opening,

an end plate secured to said end edge and closing one end of said burner, said sleeve being spaced therefrom to provide for radial inward passage of air from said duct,

an auxiliary cylindrical metal sleeve of larger diameter than said main sleeve and of smaller diameter than said cylindrical portion of said outer shell, concentric with and supported by said main sleeve at the end distant from said end plate and overlapped with said main sleeve and extending therebeyond and into and frustoconical portion of said outer shell, with air flow from said air flow duct at both ends of said auxiliary sleeve, thereby preventing the build-up of deposits of slag, and

an oil spray nozzle supported axially of said main sleeve by said end plate.

4. The burner of claim 3 having a plurality of radial air scoops at said end plate having a radially extending outer opening on one side leading from said air inlet duct radially into a general-1y horizontal opening near the center of said burner, there also being open space between said scoops for air passage from said duct into said narrow air passage and into the interior of said main sleeve.

5. A burner for fuel oil containing catalyst fines for use with boilers and the like, including in combination:

an outer metal shell having a generally cylindrical prefirewall portion and a frustoconical post-firewall portion with an axially aligned nozzle outlet of reduced size, said cylindrical portion having an end edge and having an air inlet opening extending in an axial direction along substantially all of said cylindrical portion with outwardly extending walls providing a duct tangential to said shell at said opening,

a main cylindrical metal sleeve smaller in diameter than the cylindrical portion of said shell supported concentrically within said cylindrical portion and spaced axially therewithin from both ends thereof, and providing with said cylindrical portion an annular air flow duct in communication with said air inlet opening,

an auxiliary cylindrical metal sleeve of larger diameter than said main sleeve and of smaller diameter than said cylindrical portion of said outer shell, concentric with and supported by said main sleeve at the end distant from said end plate and overlapped with said main sleeve and extending therebeyond and into said frustoconical portion of said outer shell, with air flow from said air flow duct at both ends of said auxiliary sleeve, thereby preventing the buildup of deposits of slag,

an oil spray nozzle supported axially of said main sleeve by said end plate, and

a plurality of radial air scoops at said end plate leading from said air inlet duct radially in to a point closely adjacent the axial center line of said burner.

6. A combination burner for burning either oil or gas,

according to the wishes of the user, for use with boilers and the like, including in combination:

an outer shell having a generally cylindrical portion, and an axial outlet, said cylindrical portion having an air inlet opening,

a main cylindrical sleeve supported concentrically.

within said cylindrical portion and spaced radially therefrom to define an annular 'air flow duct in communication with said air inlet opening,

an end plate closing one end of said burner and of said cylindrical portion, said sleeve being spaced axially therefrom to provide for radial inward passage of air from said duct,

an auxiliary sleeve of larger diameter than said main sleeve and of smaller diameter than said cylindrical portion of said outer shell, concentric with and supported by said main sleeve at the end distant from said end plate to provide a short overlap and extend ing therebeyond to provide air flow from said air flow duct in toward the flame at both ends of said auxiliary sleeve,

an oil spray nozzle, with an oil supply conduit, supported by said end plate axially of said main sleeve,

an annular gas tube having an axial length shorter than said sleeve and mounted around said oil spray nozzle and concentrically within said sleeve and spaced therefrom to provide a narrow annular air passage therebetween, said tube having an inner cylindrical wall with a series of narrow axially extending radial slots spaced around its circumference for projecting gas radially toward the axis of the burner,

a gas supply conduit leading into said tube, and

valve means in said supply conduits for changing from gas to oil and vice versa.

7. The burner of claim 6 having a plurality of radial air scoops at said end plate leading radially in from said air inlet duct, each having an axial outlet near the axial center line of said burner.

8. A burner capable of burning gas and fuel oil alternatively and remaining clean when burning fuel oil containing catalyst fines, for use with boilers and the like, including in combination:

an outer shell having a generally cylindrical pre-firewall portion and a frustoconical post-firewall portion with an axially aligned nozzle outlet of reduced size, said cylindrical portion having an end edge and having an axially extending tangential air inlet,

a main cylindrical sleeve smaller in diameter than the cylindrical portion of said shell supported concentrically entirely within said cylindrical portion and terminating a spaced distance from said post-firewall portion, and providing with said cylindrical portion an annular air flow duct in communication with said air inlet opening,

an end plate secured to said end edge and closing one end of said burner, said sleeve being spaced therefrom to provide for radial inward passage of air from said duct,

an auxiliary cylindrical metal sleeve of larger diameter than said main sleeve and of smaller diameter than said cylindrical portion of said outer shell, concentric with and supported by said main sleeve at the end distant from said end plate and overlapping with said main sleeve and extending therebeyond into said frustoconical portion of said outer shell with an end edge spaced therefrom to enable air to flow from said air flow duct inwardly at both ends of said auxiliary sleeve, said air flow preventing slag deposit from catalyst containing oil,

, an oil supply conduit,

an oil spray nozzle connected to said oil supply conduit and supported axially of said main sleeve therewi-thin by said end plate,

an annular gas tube having an axial length shorter than said sleeve and spaced at about the same distance from said end plate as said sleeve and mounted concentrically Within said sleeve, said gas tube being spaced radially in from said sleeve to provide a narrow'annular air passage therebetween and having an inner cylindrical wall with a series of narrow axially extending radial slots spaced around the circumference for projecting gas radially toward the axis of the burner,

a gas supply conduit leading into said gas tube, and

valve means in each said supply conduit for changing the fuel supplied to said burner from one type to the other.

9. The burner of claim 8 having a plurality of radial air scoops at said end plate having a radially extending outer opening on one side leading from said air inlet duct radially into a generally horizontal opening near the center of said burner, there also being open space between said scoops for air passage from said duct into said narrow air passage and into the area bounded by said gas tube.

10. A burner capable of burning gas and fuel oil alternatively and remaining clean when burning fuel oil con taining catalyst fines, for use with boilers and the like, including in combination:

an outer metal shell having a generally cylindrical prefirewall portion and a frustoconical post-firewall portion with an axially aligned nozzle outlet of reduced size, said cylindrical portion having an end edge and having an air inlet opening extending in an axial direction along substantially all of said cylindrical portion with outwardly extending walls providing a duct tangential t-o'said shell at said opening,

a main cylindrical metal sleeve smaller in diameter than the cylindrical portion of said shell supported concentrically within said cylindrical portion and 1 ll spaced axially in from both ends thereof, and providing with said cylindrical portion an annular air flow duct in communication with said air inlet open- 12 axial end of said zone at about the axial center line thereof, introducing a second supply of combustion air in a generally helical path from said one end further an end plate secured to said end edge and closing one 5 from the axis,

end of said burner, said sleeve being spaced thereintroducing a third supply of combustion air at the from to provide for radial inward passage of air other end of said annular zone in a generally helical from said duct, path of larger diameter than said second supply and an auxiliary cylindrical metal sleeve of larger diameter in the same axial direction as id fi t and second than said main sleeve and of smaller diameter than supplies, and said cylindrical portion of said outer shell, concenintroducing a fourth supply of combustion air beyond trio with and supported by said main sleeve at the the introduction of said third supply and in the same end distance from said end plate and overlapping axial direction from a larger diameter than said third with said main sleeve and extending therebeyond supply. into said frustoconical portion of said outer shell 12. A method for efiicient burnin of il t produce with an end edge spaced therefrom to enable air to good power output within a small length, and for preventfiow from said air flow duct inwardly at both ends ing the deposit of slag in the burning zone, even when of said auxiliary sleeve, said air flow preventing slag burning fuel oil containing catalyst fines, comprising the deposit from catalyst-containing oil, steps of: an oil supply conduit, spraying oil axially of an annular zone, an oil spray nozzle connected to said oil supply conduit introducing a first supply of combustion air from one and supported axially of said main sleeve thereaxial end of said zone at about the axial center line within by said end plate, thereof, an annular gas tube having an axial length shorter introducing a second supply of combustion air in a than said sleeve and spaced in from the end of said generally helical path from said one end farther from sleeve more distant from said end plate and mounted the axial center and closer to the inner periphery of concentrically Within said sleeve, said gas tube havthe annular zone, ing an outer cylindrical wall spaced radially from introducing a third supply of combustion air at the said sleeve to provide a narrow annular air passage other end of said annular zone in a generally helical therebetween, an inner cylindrical wall joined to said path of larger diameter than said annular zone and outer wall by end walls and having a series of narin the same axial direction as said first and second row axially extending radial slots spaced around the supplies, and circumference for projecting gas radially toward the introducing a fourth supply of combustion air beyond axis of the burner, the introduction of said third supply and in the same a plurality of radial air scoops at said end plate leadaxial direction along a frustoconical path from a ing from said air inlet duct radially in to a point larger diameter than said third supply to a smaller closely adjacent the axial center line of said burner, diameter than said second supply. a gas supply conduit leading into the space between said inner and uter alls, and References Cited by the Examiner valve means in each said conduit for changing the fuel UNITED S ES PA supplied to said burner from oil to gas and from gas 1 458 378 6/1923 Astrom 239 427 5 ll A inethod for efficient burning of oil to produce 1535886 4/1925 Zulver n 2394275 11 1 th d fo t 2,499,207 2/1950 Wolfersperger 158-4 5 POWer K P- 111 a Sm Hg an E 2,581,316 1/1952 Wolfersperger 122 134 lIlg the deposit 1n the burner of slag when burning 011 595 5 5/1952 Buckland et a]. 239 403 containing catalyst fines, comprising the steps of: 2,787 318 4/1957 wolfersperger 158 1.5

introducing oil in an axial spray,

introducing a first supply of combustion air from one EVERETT W. KIRBY, Primary Examiner. 

11. A METHOD FOR EFFICIENT BURNING OF OIL TO PRODUCE GOOD POWER OUTPUT WITHIN A SMALL LENGTH AND FOR PREVENTING THE DEPOSIT IN THE BURNER OF SLAG WHEN BURNING OIL CONTAINING CATALYST FINES, COMPRISING THE STEPS OF: INTRODUCING OIL IN AN AXIAL SPRAY, INTRODUCING A FIRST SUPPLY OF COMBINATION AIR FROM ONE AXIAL END OF SAID ZONE AT ABOUT THE AXIAL CENTER LINE THEREOF, INTRODUCING A SECOND SUPPLY OF COMBINATION AIR IN A GENERALLY HELICAL PATH FROM SAID ONE END FURTHER FROM THE AXIS, INTRODUCING A THIRD SUPPLY OF COMBINATION AIR AT THE OTHER END OF SAID ANNULR ZONE IN A GENERALLY HELICAL PATH OF LARGER DIAMETER THAN SAID SECOND SUPPLY AND IN THE SAME AXIAL DIRECTION AS SAID FIRST AND SECOND SUPPLIES, AND INTRODUCING A FOURTH SUPPLY OF COMBUSTION AIR BEYOND THE INTRODUCTION OF SAID THIRD SUPPLY AND IN THE SAME AXIAL DIRECTION FROM A LARGER DIAMETER THAN SAID THIRD SUPPLY. 